Spec (short for speculation in the sense of 'what if?' not that of specification) was the term most often used for a piece of fan fiction by the highly organised fanfic section of Anne Rice fandom. This community once loomed as large on the Internet as Goth, with its webpages, mailing lists, awards and hierarchically organised sects (such as the Coven of the Articulate) devoted to various characters in the Ricean oevre (especially the Vampire Chronicles). It was centered on the busy Usenet group alt.books.anne-rice (or ABAR).
The authors of these fanfictions would speculate on various aspects of their favourite Vampire Chronicles or Mayfair Witches characters; on their likely - or merely preferred - actions, motivations, pairings.
Their specs were increasingly gathered together in well kept spec archives all over the Net in those days. The Great SpecWriter Massacre of 2000 by Ms Rice's lawyers effectively put an end to this online fanfiction community.
Stat Queen: Gems, this spec is better than anything Anne has written in the last ten years!
Black Gems: Awww yer embarrassing meeee!
SimeWave: I can't find that spec with Louis reading Blakewhile freezing his tackle off! I was sure I'd saved it.
BleakAngel: I know the spec you mean. Don't worry, I've got a copy saved over at RueLoyale.